The purpose of this study was to investigate successive bone and vasculature changes surrounding dental implants that used metal or acrylic crown superstructure, and then compare the differences found.The Japanese monkeys having a similar occlusal pattern to humans were used in this study. Implants coated with anode oxidized titanium were implanted in the mandible molar area. After implanting, the animals were kept for 12 weeks before mounting metal or acrylic crowns, but one of them was killed after 12 weeks. Experimental animals mounted the crowns were killed after 1,4,8,12,20 weeks respectively. Using acrylic resin mocrovasculature corrosion injection method, the specimens of microvasculature cast and bone surrounding the implants were formed, and then three-dimensionally observed using scanning electron microscopy to note the successive changes in both types of tissues.Our results can be summarised as follows.1) With both metal and acrylic crowns, initiation of the vigorous bone-growth stage began approximately 4 weeks after crown mounting, and the implant body became sufficiently fixed after 8 weeks.2) When metal crowns were used, the thickness of the implantal alveolar bone surrounding the implant increased. However, with acrylic crowns, the thickness of the bone increased only slightly.With both metal and acrylic crowns, abundant blood vessels were observed in the bone marrow space of the sponge bone surrounding the implant 4 weeks after mounting. However, as time progressed the bone marrow space became smaller and the amount of blood vessels also decreased.